Automatic control system for water heaters

ABSTRACT

A control system for domestic water heaters is disclosed, incorporating a check valve between the water heater and the delivery system; the pressure differential observed between the water heater and the delivery system is then sensed to control another valve at the inlet to the water heater. Accordingly, in the event of a leak in the water heater, it is isolated from the supply line so that the pressure in the tank drops to ambient. As disclosed, the pressure drop in the tank is also sensed to isolate the tank from the source of energy, e.g., a gas valve is closed.

United States Patent [191 Deals AUTOMATIC CONTROL SYSTEM FOR WATER HEATERS [76] Inventor: Wayne S. Boals, 32046 Kingspark Ct., Westlake Village, Calif. 91361 221 Filed: Aug.19,1971 211 Appl.No.:173,204

[56] References Cited UNITED STATES PATENTS 10/1935 Junkers... 137/87 3/1947 Kehoe..... 137/94 X 5/1958 Schaub 126/362 [451 Aug. 28, 1973 3,059,662 10/1962 Parr 137/337 X 3,327,761 6/1967 Rowell 137/94 X Primary Examiner-Robert G. Nilson Attomey-Nilsson, Robbins, Wills & Berliner [57] ABSTRACT A control system for domestic water heaters is disclosed, incorporating a check valve between the water heater and the delivery system; the pressure differential observed between the water heater and the delivery system is then sensed to control another valve at the inlet to the water heater. Accordingly, in the event of a leak in the water heater, it is isolated from the supply line so that the pressure in the tank drops to. ambient. As disclosed, the pressure drop in the tank is also sensed to isolate the tank from the source of energy, e.g., a gas valve is closed.

12 Claims, 3 Drawing Figures 600205 LINE PAIENIHMuczs um DEL/V52? 5V6 TEM WA TE ,Q

HEATER BELLOWS CONTROL r 1 AUToMATJC FCONTROLSYST'EM FOR WATER HEATERS BACKGROUND AND SUMMARY "OF THE INVENTION ods of time with little or no maintenance. However, the

conditions within the reservoir tank of a heater are quite corrosive with the result that aged tanks frequently rupture. Of course, depending upon the location of the heater and the period during which it is permitted to discharge water, damage may vary from a nominal amount to a considerable loss.

In view of the threat of damage from ruptured water heaters, various systems have been proposed in the past for isolating hot water heaters from water supply lines upon the occurrence of any significant leak. For example, it has been proposed to collect leakage in a basin,

the accumulation of which actuates a device to isolate the heater from the water supply line. Of course, other forms of structures have also been proposed. However, in general, such systems as previously proposed, have not come into widespread use generally in view of economic considerations. Accordingly, a considerable need continues to exist for an economical practical, control system which may be easily installed for maintenance-free operation, to isolate a hot water heater tank from the water-supply line in the event that the heater ruptures or develops a significant leak.

In general, in accordance with the present invention, hot water from the heater is supplied through a check valve so that the delivery system may not return water to the heater, in the event of a tank rupture. A control system is then provided whereby water is supplied to the heater'only if a predetermined pressure relationship exists generally between the delivery system and the heater, e.g., across the check valve. If the tank of the water heater ruptures, a reverse pressure differential develops to actuate a control valve and isolate the water heaterfrom: thesupply line. As a consequence, potential damage fromwater discharged through a leak in the heater is quite limited. Furthermore, the reduction of pressure in the water heater to an ambient level may. be utilized, in accordance herewith-,.to-isolate the heater from an energy source as -a further safety measure.

BRIEF DESCRIPTION OF THE DRAWINGS ing a somewhatmore generalized" configuration of the system hereof; and

FIG. 3 is a vertical sectional view taken centrally through a unit which may be incorporated in the system of FIG. l.

DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENT Asrequired, a detailedillustrative embodiment of the in'vention'is disclosed herein and in that regard, the embodiment is exemplified for application to a domestic water heater. However, it is to be understood that the as limiting, but merely as a basis for the claims defining the scope in content of the invention.

Referring initially to FIG. l, the system hereof is illustrated in conjunction with a water heater H which re-. ceives cool water through a distribution or source line S and delivers water toa domestic delivery system D. Of course, the domesticsystem D may comprise the hot water pipes, valves and so on associated with a residential hot water system which is served by the water heater H.

In general, the present system monitors the ability of the hot water heater H (and contiguous plumbing) to contain pressurized water and in the event of a failure, the system isolates the water heater H from the source line S. Accordingly, the damage that can resultfrom the rupture or other failure in the water heater H is limited.

In the representative system of FIG. 1, a check valve 4 is connected between the outlet 6 of the heater Hand the delivery system D. A control unit 7 (incorporating a pressure sensor and a valve) is connected between the source line S and the intake 8 of the heater H; The control unit 7 includes a valve 9 for closing the source line S under control of a piston 10 (mechanical connection indicated by dashed line 11) that is urged downwardly by a balancing spring 12. Generally, so long as the heater H is pressurized sufficiently to support the piston 10 in a raised position, water flows: from the source line 8, past the valve 9, through the heater H and through the check valve 4 to the delivery system D. However, if the heater ruptures, the pressure loss below the piston 10 allows the piston to move downward, closing the valve 9. Thus, the heater H is isolated from the source line S.

Considering the somewhat more generalized system I of FIG. 2, the source line S is connected through a valve 13' to the inlet 14' of the water heater H. The valve 13 is controlled, as described in detail below, and is closed in the event of a rupture in the tank contained within the water heater H. The outlet 16 of the water heater H is'connected through a pipeline I8 to the domestic water delivery system D, which pipeline incorporates a check valve 20. Various forms of check valves satisfactory for use as the checkvalve 20 are well known in the prior art. Also, some existing domestic or residential water systems incorporate a cheek valve which may be readily utilized as the check valve 20in a'system as represented in FIG. 2.

The pipeline l8 affords connections across the check valve 20, i.e., tees 22 and 24 are connected respectively to ducts 26' and 28 which are in turn connected to a sensing unit 30 Thus, means are providedfor manifesting the pressure differential across the check valve 20 to develop a control signal for the valve 13.

The sensing unit 30 may take a variety of different forms, one of which is disclosed in detail below as exemplary. Functionally, the unit 30 provides a signal, e.g., mechanical, electrical, hydraulic or so on, which is applied, as indicated by the dashed line 32, to control the valve 13. Essentially, the operation of the unit 30 is to close the valve 13 upon the occurrence of a pressure in the duct 26 which is significantly greater than the pressure in the duct 28.

During routine operation of the system of FIG. 2, the valve 13 is open with the result that waterflows into the water heater H on demand. Somewhat similarly, water flows out of the water heater H through the check valve 20 on demand as it is dispensed from the domestic system D. Of course, when a tap valve (not shown) in the domestic system D is opened, the pressure therein is relieved permitting flow through the check valve 20 and the pipeline 18. On closure of the tap valve in the domestic system D, the pressures across the check valve 20 are somewhat balanced with the result that the valve 20 closes.

In the event of a failure in the water heater H as by a rupture in the tank, the pressure therein is substantially reduced. Consequently, an inverse pressure occurs across the check valve 20, either as a result of the pressurization of the domestic system D, static head, or a combination of both. Consequently, the check valve 20 closes and therby maintains the reverse pressure differential which actuates the sensing unit 30. Consequently, the valve 13 is closed by the sensing unit 30 isolating the water heater H from the pressurized pipeline S. As a result, the water heater H is reduced to ambient pressure and the damage is limited to that caused by discharging the content of the heater.

Considering another aspect of the system, the pressure in the water heater H is also sensed by a control bellows 36 which is connected to the outlet 16 through a duct 38. The control bellows is in turn connected (as indicated by a dashed line 40) to a valve 42 in the gas supply line 44 for the heater H. Consequently, whenthe pressure in the water heater H is reduced essentially to ambient, the control bellows 36 closes the valve 42 to isolate the heater H from its source of fuel. Of course, a similar arrangement may be provided by the utilization of a switch to isolate a water heater from a source of electrical energy as well known in the prior art.

The system of FIG. 2 may be embodied in various applications using a wide variety of different components. As indicated above, a variety of check valves may be employed to function in the capacity of the check valve 20. Although several structural forms are usable, a unitary structure for the valve I3 and sensing unit has been developed in accordance herewith embodying the components as indicated by the block 50. That structure is shown in FIG. 3 and will now be considered.

In general the unitary sensing valve structure as shown in FIG. 3 incorporates a diaphragm 52 for sensing the pressure differential of interest. Of course, various other sensing structures, e.g., bellows, cylinders or the like might well be employed. The diaphragm 52 may comprise any of a variety of flexible materials as well known in the prior art and is supported about its periphery between a cap 54 and a body 56. These members are affixed together by studs 58, and define a chamber 60 into which pressure differentials are introduced across the diaphragm 52.

The cap 54 and the upper (as shown) side of the diaphragm 52 define a space 60A while the lower side of the diaphragm and the body 56 define a lower space 608. The lower space 60B is pressurized through a port 62 which is connected by a duct 64 to the domestic delivery system D as indicated in FIGS. land 2. The cap 54 also receives a plunger 66 which: is urged to an upward position by a spring 68 and which is sealed in the cap 54 by a seal 70 which may comprise an 0" ring, for example. The plunger 66 is provided concentrically in the cap 54 to engage a hollow concentric guide shaft 72 which is affixed at the center of the diaphragm 52 by a lock nut 73 and extends through a seal 74 in the body 56 to axially engage a valve poppet 76 which is fixed in the body 56. The lower end 75 of the shaft 72 is scalloped to provide a passage from the space 60A to the valve chamber 77.

In the valve chamber 77, the poppet 76 is held concentric within the body 56 by a closure plug 78 which telescopically receives the poppet 76 with a spring 80 and a seal 82, in telescopic relationship. The closure plug 78 is threadably afi'lxed in the body 56 providing support for the spring80 to urge the poppet 76 upwardly for providing a sealing engagement between an annular ring 84 (received in the poppet 76) and a mating annular knife edge 86 defined in the body 56.

The lower portion of the valve chamber 77 is connected to a threadably received pipe 89 for connection to the line providing source water, e.g., source S, FIGS. 1 and 2. Another port in the body 56 extends from the upper portion of the chamber 77 and threadably receives a pipe 92 which is connected to the water heater H as illustrated in'FIG. 1. Thus, recapitulating, the pipe 89 (main line connection) is connected across a valve (poppet 76) to the pipe 92 (heater connection) and that valve is controlled by the pressure differential developed between the chamber 60A (essentially heater pressure) and the chamber 60B (domestic system pressure).

The control valve configuration of FIG. 3 may be variously manufactured in accordance with well known techniques of the prior art. Specifically, the components may be cast and/or machined of various materials as brass and may be assembled simply by threadably engaging the elements as shown.

In operation of the structure as shown in FIG. 3, it may be necessary upon installation to depress the plunger 66 which in turn moves the shaft 72 axially to similarly move the poppet 76. As a consequence, the valve incorporated in the structure is opened, permitting free flow from the duct 89 through the passage or chamber 77 to the duct 92. After free flow has been established and the various passages in the system filled with fluid, the plunger 66 is released allowing the apparatus to operate in an independent manner. As indicated above, the essential operation of the system is to close the valve poppet 76 against the knife edge 86 in the eventthat the pressure across the diaphragm attains a predetermined level. Specifically, if the pressure in the space 60A (heater pressure) drops to a significant level below the pressure in the space 608 (domestic system) the spring 80 urges the poppet 76 and the shaft 72 upwardly so that the poppet seats the seal ring 84 against the knife edge 86. Consequently, the water heater H (FIG. 1) is isolated by closure of the valve as represented by the valve V in FIG. 1.

Having thus described the system hereof with respect to the figures and presented certain exemplary details thereof with regard to the form and structures employed, adaptations and modifications will be rapidly apparent. Accordingly, the scope hereof shall be determined in accordance with the claims as set forth below.

What is claimed is:

l. A fluid control system for use in association with a tank that is to be coupled to a fluid source, which tank provides fluid to a delivery system, comprising:

sensing means for sensing a pressure differential between said tank and said delivery system;

and

valve means coupled to said sensing means and con nected between said tank and said fluid source, said valve means-being responsive to allow the passage of fluid from said fluid source to said tank on demand I by said delivery system, providing said sensing means senses a predetermined pressure differential between said tank and said delivery system.

2. A system according to claim 1 further including check valve means connected between said delivery system and said tank whereby to limit reverse flow therebetween.

3. A system according to claim 2 wherein said means for sensing comprises a pressure displacement means for providing a mechanical displacement to control said valve means.

4. A system according to claim 3 wherein said pressure displacement means and said control valve means comprise: a unitary housing defining a pressure chamber and a valve seat; separation means for separating said pressure chamber into at least two spaces, and responsive to the pressure differential therebetween; and poppet means for matingly engaging said seat under control of said separation means.

5. A system according to claim 3 wherein said tank comprises a domestic hot water heater.

6. A system according to claim 5 wherein said tank includes heating means for connection to a source of energy and further including means for sensing said isolation of said tank to disconnect said heating means from said source of energy.

7. A system according to claim 5 wherein said pressure displacement means and said control valve means comprise: a unitary housing defining a pressure chamber and a valve seat; separation means for separating said pressure chamber into at least two spaces, and responsive to the pressure differential therebetween; and poppet means for matingly engaging said seat under control of said separation means.

8. A system according to claim 5 wherein said tank includes heating means for connection to a source of energy and further including means for sensing said isolation of said tank to disconnect said heating means from said source of energy and wherein said pressure displacement means and said control valve means comprise: a unitary housing defining a pressure chamber and a valve seat; separation means for separating said pressure chamber into at least two spaces, and responsive to the pressure differential therebetween and poppet means for matingly engaging said seat under control of said separation means.

9. A system according to claim 8 wherein said separation means comprises a flexible diaphragm.

10. A system according to claim 2 wherein said tank includes heating means for connection to a source of energy and further including means for sensing said isolation of said tank to disconnect said heating means from said source of energy.

11. A system according to claim 1 wherein said predetermined pressure differential to allow the passage of fluid results providing said tank is effectively closed.

12. A system according to claim 11 wherein said valve means is responsive to a predetermined pressure differential wherein fluid pressure in said tank exceeds fluid pressure in said delivery system. 

1. A fluid control system for use in association with a tank that is to be coupled to a fluid source, which tank provides fluid to a delivery system, comprising: sensing means for sensing a pressure differential between said tank and said delivery system; and valve means coupled to said sensing means and connected between said tank and said fluid source, said valve means being responsive to allow the passage of fluid from said fluid source to said tank on demand by said delivery system, providing said sensing means senses a predetermined pressure differential between said tank and said delivery system.
 2. A system according to claim 1 further including check valve means connected between said delivery system and said tank whereby to limit reverse flow therebetween.
 3. A system according to claim 2 wherein said means for sensing comprises a pressure displacemeNt means for providing a mechanical displacement to control said valve means.
 4. A system according to claim 3 wherein said pressure displacement means and said control valve means comprise: a unitary housing defining a pressure chamber and a valve seat; separation means for separating said pressure chamber into at least two spaces, and responsive to the pressure differential therebetween; and poppet means for matingly engaging said seat under control of said separation means.
 5. A system according to claim 3 wherein said tank comprises a domestic hot water heater.
 6. A system according to claim 5 wherein said tank includes heating means for connection to a source of energy and further including means for sensing said isolation of said tank to disconnect said heating means from said source of energy.
 7. A system according to claim 5 wherein said pressure displacement means and said control valve means comprise: a unitary housing defining a pressure chamber and a valve seat; separation means for separating said pressure chamber into at least two spaces, and responsive to the pressure differential therebetween; and poppet means for matingly engaging said seat under control of said separation means.
 8. A system according to claim 5 wherein said tank includes heating means for connection to a source of energy and further including means for sensing said isolation of said tank to disconnect said heating means from said source of energy and wherein said pressure displacement means and said control valve means comprise: a unitary housing defining a pressure chamber and a valve seat; separation means for separating said pressure chamber into at least two spaces, and responsive to the pressure differential therebetween and poppet means for matingly engaging said seat under control of said separation means.
 9. A system according to claim 8 wherein said separation means comprises a flexible diaphragm.
 10. A system according to claim 2 wherein said tank includes heating means for connection to a source of energy and further including means for sensing said isolation of said tank to disconnect said heating means from said source of energy.
 11. A system according to claim 1 wherein said predetermined pressure differential to allow the passage of fluid results providing said tank is effectively closed.
 12. A system according to claim 11 wherein said valve means is responsive to a predetermined pressure differential wherein fluid pressure in said tank exceeds fluid pressure in said delivery system. 